Dupont Delrin® rod and Acetal Rods

Many of our clients assume that Delrin® rod and Acetal rod are the same thing. This is not quite true.

Yes, all Dupont Delrin® rod is Acetal rod, but not all Acetal rod is Delrin® rod. Dupont is the maker of Dupont Delrin® resins

Delrin® is the trade name for Homopolymer Acetal made by Dupont. This is the most recognized of all trade names for Acetal materials, but far from the only available Acetal material.
The Co-Polymer Acetal is produced by a wide variety of large plastic manufacturers, BASF is probably one of the largest and most well known. Some main resin names are: BASF Ultraform® H4320, Kepital® F10-02, or Hostaform® M25.

While Delrin® is a wonderful material, in larger cross sections or larger diameters, the Delrin® brand Homo-Polymer can exhibit center line porosity, or soft centers. This can sometimes be seen with the naked eye, and is a darker white in a normally milky white natural colored material. This center line porosity can cause problems in some applications. This porosity can cause leakage of fluid if under pressure, or soft center’s of Delrin® Rod and Delrin® Sheet.

This should not stop you from considering Delrin® though. Many other properties of the Delrin® resin are superior to the Co-Polymer resins. These properties are:

General PropertyASTM
Typical Value
Unfilled Delrin®

Typical Value
Unfilled Co-Polymer
Specific Gravity D7921.421.40
Tensile Strength YieldD6389,600 – 11,0009,000 – 10,200
Tensile ModulusD638450,000400,000
Izod Impact – NotchedD2561.21.0
Hardness – RockwellD785M94M90
Deflection Temp @ 264psiD648257220
Deflection Temp @ 66 psiD648347335
Water Absorption @ 24 hrs
Co. Thermal ExpansionD6966.83X10-55.4X10-5

Some key properties for Delrin® are: higher tensile strength, increased Izod impact, higher deflection temperatures and it is slightly harder. The co-efficient of thermal expansion is a bit higher, and needs to be considered when designing a new part. Delrin brand material also comes in several resin variations, including: Delrin® 150 and Delrin® 507, contact us for details.

Many of our clients prefer the Delrin® brand rod and sheet for small machined parts. This is due to the increase in a few key properties, and of course brand recognition.

Both resins meet the standard ASTM-D-6778, and the cancelled specs, L-P-395 and ASTM-D-4181.Comparing Dupont Delrin to Acetal Copolymer

The Acetal family of plastic resins are excellent for wear resistance, great mechanical strength, and superior machining properties. It is available in a huge range of sizes and shapes. Click here for more details on Acetal – Delrin® Rod, and sometimes referred to as plastic dowel. We also have the capacity to supply colored Acetal – Delrin® rod; click here from more details on the colored Acetal material.

Similar materials to Acetal – Delrin® are Nylon Rod, PET Rod and Noryl® Rod. Most materials are available as round rod, square rod, bar, strip, sheet and plate.

Please contact us for more details on these and other plastic materials. For a comparison chart of plastic materials click here: Plastic Materials Selection Guide


Is Delrin and UHMW the same?

Dupont Delrin® is the common name for homopolymer acetal (POM-H). UHWM is a member of the Polyolefin family, and much different that Delrin®. The Dupont Delrin® has slightly better mechanical properties than copolymer acetal, but often can have a low density center, especially in large cross-sections. Dupont Delrin®, like all Acetal materials, is easy to machine and has very low moisture absorption, and provides an excellent machined surface finish.

What is the difference between Delrin and Teflon®?

Dupont Delrin® is an Acetal or polyoxymethylene (POM-H) and it is a semi-crystalline, non-amorphous type of thermoplastic. Delrin®, which is the DuPont brand name for Acetal, is a homopolymer. It comes in both black and white. One important difference between Acetal Copolymer and the homopolymer Delrin resin is that Acetal tends to have centerline porosity. Teflon® is also a tradename for the original PTFE resin produced and invented by Dupont, and once processed into a shape it can only be called PTFE.

Which is better, Dupont Delrin or Acetal Copolymer?

Acetal is the common name for a family of thermoplastics with the chemical name 'PolyOxyMethylene', or POM. Acetal is available in two general types of resins: Copolymer Acetal (POM-C), and Homopolymer Acetal (POM-H) commonly called Dupont Delrin®. Each type of acetal has its own set of advantages and disadvantages. Which one is better? It depends on the physical properties you are looking for.

What kind of material is Delrin?

Acetal Homopolymer (POM-H) or Dupont Delrin® is a semi-crystalline plastic which offers an excellent balance of physical properties that bridge the gap between metals and plastics. The Dupont Delrin® possesses high tensile strength, excellent creep resistance and toughness. It also exhibits low moisture absorption while providing an excellent wear resistance.

Are Dupont Delrin Rod and Acetal Rod the same thing?

No, they are not the same. The Dupont Delrin® homopolymer acetal or POM-H offers slightly higher mechanical properties than acetal copolymer, but may contain a soft or low density center (also known as 'center line porosity'), this is especially true in large cross-sections of Dupont Delrin. In addition, Dupont Delrin® also is slightly less chemical resistance than the copolymer acetal alson known as POM-C.